The proposal aims to (i) identify the proteins associated with ribosomes in the cell; (ii) determine the nature of the interactions of these ribosome- associated proteins with the ribosome and other proteins; (iii) characterize the response of ribosome-associated proteins to different stresses and changes in cell cycle. The discovery of proteins involved in stress responses that use the ribosome for localization will further our understanding of stress responses in the yeast cell and pathways that use these proteins as targets. The proteins that regulate growth related responses also have implications in health sciences, and targets. The proteins that regulate growth related responses also have implications in health sciences, and homologs in human cells may serve as therapeutic targets. The research is designed in three separate parts to achieve the stated goals. The first part is designed to identify the proteins associated with the ribosome, using affinity purification schemes, two dimensional gel electrophoresis, and mass spectrometry and protein sequencing. The second part is designed to screen for a subset of proteins that play a role in translation and localize specifically within the cell using standard reagents and translation assays. The third part is designed to examine how this subset of proteins responds to stress conditions and cell cycle changes, using methods to tract localization in vivo. Focus will be placed on explaining the response of these proteins in terms of cellular physiology and molecular interactions.